The Raychaudhuri Equation in General Theory of Relativity derived by Amal Kumar Raychaudhuri (AKR) arrived amid a time when he was a teacher at Ashutosh College, Calcutta during 1950. The equation is now grabbing eyeballs after the Royal Swedish Academy of Sciences awarded a share in 2020 Nobel for Physics to Roger Penrose for his findings pertinent to Black Holes.
Raychaudhuri had published an equation in the journal Physical Review in 1955 that Penrose and celebrated cosmologist Stephen Hawking employed in 1969 for a mathematical description of Back Holes. Nevertheless, Einstein’s General Theory of Relativity had proved Black Holes’ existence but he himself didn’t assume their actuality.
“AKR had used geometry to arrive at a singularity where laws of physics break down and physical quantity becomes infinitely large in the context of gravity and where space time becomes infinitely large,” TOI quoted IISER Physical Sciences department, Prof. Narayan Banerjee, who had attended a workshop at the Jadavpur University in 1987 when Raychaudhuri and Penrose had first met each other, as saying.
“This equation was the building block on which the Penrose-Hawking singularity theorems published in 1969 were based. Both Penrose and Hawking have acknowledged Raychaudhuri’s contribution on numerous occasions in published papers and books,” added Banerjee.
When Soviet physicist, Lev Landau a bit later, also derived the same equation that Raychaudhuri had derived, it was after then only when the scientific community accepted Raychaudhuri Equation as a principal contribution.
Raychaudhuri’s benefactions are priceless and he will still remain a father figure in Indian relativity community, despite not finding a mention in Nobel citation.